HomeMy WebLinkAboutLANDINGS OFFICE PARK PUD - Filed GR-GEOTECHNICAL REPORT/SOILS REPORT -PRELIMINARY GEOTECHNICAL ENGINEERING REPORT
MASTERS PROPERTY
FORT COLLINS, COLORADO
ELI PROJECT NO. 20945233
November 4, 1994
Prepared for.
LAGUNITAS COMPANY
3303 SOUTH COLLEGE AVENUE, SUITE 200
FORT COLLINS, COLORADO 80525
ATTN: MR. JOHN PROUTY
Prepared by.
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
301 North Howes
Fort Collins, Colorado 80521
Empire Laboratories, Inc
A Division of The Terracon Companies, Inc.
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
P.O. Box 503.301 No. Howes
Fort Collins, Colorado 80522
303) 484-0359
Fax (303) 484-0454
Chester C. Smith, P.E.
Larry G. O'Dell, P.E.
Neil R. Sherrod, C.P.G.
November 4, 1994
Lagunitas Company
3303 South College Avenue, Suite 200
Fort Collins, Colorado 80525
Attn: Mr. John Prouty
Rem Preliminary Geotechnical Engineering Report,
Masters Property, Fort Collins, Colorado
ELI Project No. 20945233
Empire Laboratories, Inc. (ELI) has completed a preliminary geotechnical engineering
exploration for the proposed office park to be located on Boardwalk Drive between Landings
Drive and JFK Parkway in southwest Fort Collins, Colorado. This study was performed in
general accordance with our proposal number D2094254 dated September 29, 1994.
The results of our engineering study, including the boring location diagram, laboratory test
results, test boring records, and the preliminary geotechnical recommendations needed to
aid in the preliminary design and earth connected phases of this project are attached.
The subsurface soils consisted of sandy lean clay underlain by claystone-siltstone-sandstone
bedrock. The information obtained by the results of field exploration and laboratory testing
completed for this study indicates the soils at the site have low expansive potential and the
siltstone-claystone bedrock exhibits moderate to high swell potential. The soils exhibit
moderate bearing characteristics, and the bedrock exhibits high bearing characteristics.
Based on the geotechnical engineering analysis, subsurface exploration and laboratory test
results, we recommend the proposed structures founded in or within 3 feet of the expansive
siltstone-claystone bedrock be supported on a grade beam and straight shaft pier foundation
system. Structures founded in the sandstone bedrock or upper soils underlain by sandstone
bedrock may be supported by spread footing foundations. Due to the engineering
characteristics of near surface soil and bedrock, it is our opinion that if no movement can
be tolerated, structural floor systems should be considered. Slab -on -grade may be utilized
for interior floor systems provided the owner is willing to accept the risk of movement and
care is taken during placement and compaction of the subgrade soils.
Offices of The Terracon Companies, Inc. Geotechnical, Environmental and Materials Engineers
Arizona N Arkansas a Colorado 0 Idaho 0 Illinois m Iowa a Kansas ® Minnesota
Missouri M Montana M Nebraska al Nevada 9 Oklahoma m Texas Utah u Wyoming
QUALITY ENGINEERING SINCE 1966
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Preliminary Geotechnical Engineering Exploration
Lagunitas Company
ELI Project No. 20945233
Terracon
Other design and construction details, based upon geotechnical conditions, are presented
in the report.
We appreciated being of service during the preliminary geotechnical engineering phase of
this project, and are prepared to assist during the final geotechnical and construction phases
as well. If you have any questions concerning this report or any of our testing, inspection,
design and consulting services, please do not hesitate to contact us.
Sincerely,
EMPIRE LABORATORIES, INC.
A Division of The Terracon Companies, Inc.
Neil R. Sherr' d
Senior Engineering Geologist
Reviewed by:
644, C;a (0(QCV\
Larry G. O'Dell, P.E.
Office Manager
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Preliminary Geotechnical Engineering Exploration Terracon
Lagunitas Company
ELI Project No. 20945233
TABLE OF CONTENTS
Page No.
Letter of Transmittal ............................................... ii
INTRODUCTION ................................................ 1
PROPOSED CONSTRUCTION ...................................... 1
SITE EXPLORATION ............................................. 1
Field Exploration.......................................... 2
LaboratoryTesting ......... ....................... ...... 2
SITE CONDITIONS ........ ....................................... 3
SUBSURFACE CONDITIONS ....................................... 3
Geology................................................ 3
Soil and Bedrock Conditions ... ................................ 3
Field and Laboratory Test Results ............................... 4
Groundwater Conditions ..................................... 4
PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS .................. 5
Site Development Considerations ............................... 5
SiteClearing ........................................ 5
Utility and Site Grading ................................. 5
Fill Materials ........................................ 6
Foundation Systems ........................................ 6
Floor Slab Design and Construction ............................. 6
Compliance......................................... 7
PRELIMINARY GENERAL COMMENTS ................................ 7
i 6
Preliminary Geotechnical Engineering Exploration Terracon
Lagunitas Company
ELI Project No. 20945233
TABLE OF CONTENTS (Cont'd)
APPENDIX A
Figure No.
SitePlan ................................................. 1
Logs of Borings ..................................... Al thru A3 .
APPENDIX B
Consolidation Test ......................................... B1
Summary of Test Results .................................... B2
APPENDIX C: GENERAL NOTES
Drilling & Exploration ....................................... C1
Unified Soil Classification .................................... C2
Bedrock Classification, Sedimentary Bedrock ....................... C3
Laboratory Testing, Significance and Purpose ...................... C4
ReportTerminology ........................................ C5
PRELIMINARY GEOTECHNICAL ENGINEERING REPORT Terracon
MASTERS PROPERTY
FORT COLLINS, COLORADO
ELI Project No. 20945233
November 4, 1994
INTRODUCTION
This report contains the results of our preliminary geotechnical engineering exploration for
the proposed office buildings to be located on Boardwalk Drive between JFK Parkway and
Landings Drive in south Fort Collins, Colorado. The site is located in the Southwest 1 /4 of
Section 36, Township 7 North, Range 69 West of the 6th Principal Meridian.
The purpose of these services is to provide information and preliminary geotechnical
engineering recommendations relative to:
subsurface soil and bedrock conditions
groundwater conditions
site development considerations
preliminary foundation design and construction
preliminary floor slab design and construction
utilities
The conclusions and recommendations contained in this report are based upon the results
of field and laboratory testing, engineering analysis, and experience with similar soil
conditions, structures and our understanding of the proposed project.
PROPOSED CONSTRUCTION
The site is to be developed as a commercial office park with several one- or two-story slab -
on -grade office buildings proposed for the site. Parking areas and/or drives are planned
adjacent to the buildings. Site grading plans were not available prior to preparation of this
report. However, it is anticipated that cuts and fills will be less than 3 to 4 feet throughout
the project area.
1 SITE EXPLORATION
The scope of the services performed for this project included site reconnaissance by an
engineering geologist, a subsurface exploration program, laboratory testing and engineering
analysis.
Preliminary Geotechnical Engineering Exploration
Lagunitas Company
ELI Project No. 20945233
Terracon
Field Exploration: A total of three test borings were drilled on October 5, 1994 to
approximate depths of 14 to 14% feet at the locations shown on the Site Plan, Figure 1.
The borings were drilled within the area of the proposed building construction. All borings
were advanced with a truck -mounted drilling rig, utilizing 4-inch diameter solid stem auger.
The borings were located in the field by pacing from existing fence Lines. The accuracy of
boring locations should only be assumed to the level implied by the methods used.
Continuous lithologic logs of each boring were recorded by the engineering geologist during
the drilling operations. At selected intervals, samples of the subsurface materials were
taken by pushing thin -walled Shelby tubes, or by driving split -spoon samplers.
nt were obtained b driving the split -spoon into thePenetrationresistancemeasurementsyg
subsurface materials with a 140-pound hammer falling 30 inches. The penetration
resistance value is a useful index to the consistency, relative density or hardness of the
materials encountered.
Groundwater measurements were made in each boring at the time of site exploration, and
one day after drilling.
Laboratory Testing: All samples retrieved during the field exploration were returned to the
laboratory for observation by the project geotechnical engineer, and. were classified in
accordance with the Unified Soil Classification System described in Appendix C. Samples
of bedrock were classified in accordance with the general notes for Bedrock Classification.
At that time, the field descriptions were confirmed or modified as necessary, an applicable
laboratory testing program was formulated to determine engineering properties of the
subsurface materials. Boring logs were prepared and are presented in Appendix A.
Selected soil and bedrock samples were tested for the following engineering properties:
Water content ® Expansion
Dry density ® Atterberg limits
Consolidation ® Water soluble sulfate
The significance and purpose of each laboratory test is described in Appendix C. Laboratory
ttest results are presented in Appendix B, and were used for the geotechnical engineering
analyses, and the development of foundation and earthwork recommendations. All
2
Preliminary Geotechnical Engineering Exploration Terracon
Lagunitas Company
ELI Project No. 20945233
laboratory tests were performed in general accordance with the applicable ASTM, local or
other accepted standards.
SITE CONDITIONS
A mobile home is located on the east half of the site, and an existing house is located in the
West portion of the area. Several outbuildings and fenced dog pens are also located on the
property. The site is vegetated with sod, native grasses and several large trees. The area
slopes to the south toward Boardwalk Drive and has positive drainage in this direction. The
property is bordered to the west, north and east by fences, to the south by Boardwalk
Drive, and to the east by Landings Drive.
SUBSURFACE CONDITIONS
Geology: The proposedoed area is located within the Colorado Piedmont section of the Great
Plains physiographic province. The Colorado Piedmont, formed during Late Tertiary and
1 Early Quaternary time (approximately 2,000,000 years ago), is a broad, erosional trench
which separates the Southern Rocky Mountains from the High Plains. Structurally, the site
lies along the western flank of the Denver Basin. During the Late Mesozoic and Early
Cenozoic Periods (approximately 70,000,000 years ago), intense tectonic activity occurred,
causing the uplifting of the Front Range and associated downwarping of the Denver Basin
to the east. Relatively flat uplands and broad valleys characterize the present-day
topography of the Colorado Piedmont in this region. The site is underlain by the Cretaceous
Pierre Formation. The Pierre shale consisting of sandstones, siltstones and claystones
underlies the site at depths of 3% to 4%2 feet below the surface. The Pierre shale is
overlain by residual soils of Pleistocene and/or Recent Age.
and Bedrock Conditions: As resented on the Logs of Boring, the subsurface soils areSoilap99
presented as follows:
Fill Material: A /: to 1'h foot layer of fill material was encountered at the surface
of the three borings drilled at the site. The fill consists of sandy lean clay with minor
amounts of gravel. The fill is dry and very stiff to hard.
Sandy Lean Clay: This stratum underlies the fill and extends to the bedrock below.
The sandy lean clay is moderately plastic, is dry to moist and stiff in consistency.
K
Preliminary Geotechnical Engineering Exploration
Terracon
Lagunitas Company
ELI Project No. 20945233
e Claystone-Siltstone-Sandstone Bedrock: The bedrock was encountered at depths
of 3% to 4% feet below the surface and extends to greater depths. The bedrock
in Boring 1 consists of claystone-siltstone underlain by sandstone. The sandstone
e was encountered below the upper soils in Boring 2, and claystone-siltstone was
encountered below the upper subsoils in Boring 3. The underlying firm bedrock is
hard and well cemented.
1
Test Results: Laboratory test results indicate the clay subsoils areFieldandLaboratoryryY dry
to moist and stiff and exhibit low swell potential and low to moderate bearing
characteristics. The siltstone-claystone bedrock exhibits moderate to high swell potential,
and the sandstone-siltstone-claystone exhibits high to very high bearing characteristics.
d Groundwater Conditions: Groundwater was not encountered in the test borings at the time
of field exploration nor when checked one day after drilling. These observations represent
only current groundwater conditions, and may not be indicative of other times, or at other
locations. Groundwater levels can be expected to fluctuate with varying seasonal and
weather conditions.
Based upon review of U.S. Geological Survey Maps ('Hillier, et al, 1983), regional
groundwater beneath the project area predominates in colluvial, landslide or windblown
materials, or in fractured weathered consolidated sedimentary bedrock located at a depth
near ground surface. Seasonal variations in groundwater conditions are expected since the
aquifer materials may not be perennially saturated. Groundwater is generally encountered
at depths ranging from 5 to 20 feet below ground surface; depth to seasonal groundwater
is generally 10 feet or less.
Zones of perched and/or trapped groundwater may also occur at times in the subsurface
soils overlying bedrock, on top of the bedrock surface or within permeable fractures in the
bedrock materials. The location and amount of perched water is dependent upon several
factors, including hydrologic conditions, type of site development, irrigation demands on or
adjacent to the site, fluctuations in water features, seasonal and weather conditions.
Hillier, Donald E.; Schneider, Paul A., Jr.; and Hutchinson, E. Carter, 1983, Depth to Water Table (1979) in the Bou/der-Fort
Co/Gns-Greeley Area, Front Range Urban Corridor, Colorado, United States Geological Survey, Map 1-855-I.
4
Preliminary Geotechnical Engineering Exploration Terracon
Lagunitas Company
ELI Project No. 20945233
PRELIMINARY CONCLUSIONS AND RECOMMENDATIONS
o Site Development Considerations: The site appears suitable for the proposed construction. p PP P P
Site Clearing:
1. Strip and remove existing vegetation, debris, and other deleterious materials
from proposed building and pavement areas. All exposed surfaces should be
free of mounds and depressions which could prevent uniform compaction.
2. If unexpected fills or underground facilities are encountered during siteP9
clearing, such features should be removed and the excavation thoroughly
cleaned prior to backfill placement and/or construction. All excavations
should be observed by the geotechnical engineer prior to backf III placement.
3. Stripped materials consisting of vegetation and organic materials should be
wasted from the site, or used to revegetate exposed slopes after completion
of grading operations.
4. Demolition of the existing buildings should include removal of any
foundations. All material derived from the demolition of existing structures
should be removed from the site and not be allowed for use in any on -site
fills.
5. All exposed areas which will receive fill should be scarified to a minimum.
depth of 8 inches, conditioned to near optimum moisture content, and
compacted.
Utility and Site Grading:
1. It is anticipated that excavations in the upper subsoils and weathered bedrock
for the proposed construction can be accomplished with conventional
earthmoving equipment.
2. Excavations penetrating the bedrock may require the use of specializedOheavy-duty equipment, such as a large track -mounted backhoe.
Preliminary Geotechnical Engineering Exploration Terracon
Lagunitas Company
ELI Project No. 20945233
e
3. If excavations need to penetrate the well -cemented sandstone, blasting may
be needed to facilitate rock break up and removal.
4. Groundwater seepage should be anticipated for excavations approaching the
level of the bedrock. Ptymping from sumps may be utilized to control water
within the excavations. Well points may be required for significant
groundwater flow or where excavations penetrate groundwater 'to a
significant depth.
Fill Materials:
1. On -site bedrock materials are not recommended for use beneath structural
ares of the site, or as backfill. Should bedrock materials be used for general
site grading, placement in fills at non-structural locations on the site is
recommended.
Foundation Systems: Due to the presence of moderately to highly .expansive siltstone-
claystone bedrock on the site, a grade beam and drilled pier foundation system is
recommended for support of the proposed structures founded in or within 3 feet of the
expansive siltstone-claystone bedrock. Straight shaft piers, drilled a minimum of 3 feet into
the firm or harder bedrock with a minimum shaft length of 10 feet, should be anticipated.
Due to the presence of low swelling soils and sandstone bedrock in the western portion of
the site, spread footing foundations bearing upon sandstone, undisturbed soils and/or
engineered fill are recommended for support of proposed structures in the western portion
of the site.
Additional testing should be done prior to final design after building locations have been
finalized.
Perched. groundwater may occur at times since the subsurface soils are relatively
impermeable and tend to trap water. Completion of site development, including installation
of landscaping and irrigation systems, will likely lead to perched groundwater development.
Floor Slab Design and Construction: The variability of the existing soils at approximate slab
subgrade elevation could result in differential movement of floor slab -on -grade should
expansive siltstone-claystone become elevated in moisture content. Use of structural floor
systems, structurally supported independent of the subgrade soils, is a positive means of
Preliminary Geotechnical Engineering Exploration Terracon
Lagunitas Company
ELI Project No. 20945233
eliminating the potentially detrimental effects of floor movement in these areas. However,
if the owner is willing to assume the risk of possible slab movement, slab -on -grade
construction may be a reasonable alternative.
In the western portion of the site, low expansive soils and bedrock or engineered fill will
support the floor slab. Some differential movement of a slab -on -grade floor system is
possible should the subgrade soils become elevated in moisture content. Such movements
are considered within general tolerance for normal slab -on -grade construction.
Compliance: Recommendations for slabs -on -grade, foundations and pavement
elements supported on compacted fills or prepared subgrade depend upon
compliance with "Earthwork" recommendations. Additional geotechnical and
earthwork recommendations should be provided prior to final design and
construction. To assess compliance, observation and testing should be performed
under the direction of the geotechnical engineer.
PRELIMINARY GENERAL COMMENTS
It should be noted that this was a preliminary investigation and the foundation systems
recommended in this report are based on preliminary tests. Due to variations in soil
conditions encountered at the site, it is recommended that additional test borings be made
prior to final design. Samples obtained from the borings should be tested in the laboratory
to provide a basis for evaluating subsurface conditions.
This report has been prepared for the exclusive use of our client for specific application to
the project discussed and has been prepared in accordance with generally accepted
geotechnical engineering practices. No warranty, express or implied, is made. This report
has been prepared to aid in the evaluation of the property and to assist the architect and/or
engineer in the preliminary design of this project.
This report is for the exclusive purpose of providing preliminary geotechnical engineering
and/or testing information and recommendations. The scope of services for this project
does not include, either specifically or by implication, any environmental assessment of the
site or identification of contaminated or hazardous materials or conditions. If the owner is
concerned about the potential for such contamination, other studies should be undertaken.
7
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LOG OF BORING No. 1 Page 1 of 1
CLIENT
Lagoo tas Company.
ARCHITECTIENGINEER
SITE Broadwalk & Landings Drive
Fort Collins, Colorado
PROJECT
Proposed Office Park
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THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, -THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
Empire LaboratorleS
Incorporated
Division of Teftcon
BORING STARTED 10-5-94
WL Q NoneW.D. None A.B. BORING COMPLETED 10-5-94
WL RIG CMEE-55 FOREMAN DML
V L Water checked 1 day A.B. APPROVED N1tS JOB k 20945233
LOG OF 90RING No. 2 Page 1 of 1
CLIENT ARCHITECT/ENGINEER
Lagunitas Company
SITE Broadwalk & Landings Drive PROJECT
Fort Collins, Colorado Proposed Office Park
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THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL.AND ROCK TYPES: IN -SITU, THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS
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BORING STARTED 10-5-94
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IncorporatedL- WL RIG CME-55 FOREMAN DML
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WL Water checked 1 day A.B. APPROVED NRS JOB # 20945233
LOG OF BORING No. 3 Page 1 of 1
CLIENT ARCHITECTIENGINEER
Lagunitas Company
SITE Broadwalk & Landings Drive PROJECT
Fort Collins, Colorado Proposed Office Park
SAMPLES TESTS
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BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN -SITU, THE. TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 10-5-94
Empire LaboratoriesWLNoneW.D.- s None A.B. BORING COMPLETED 10-5-94
Incorporated RIG CME-55 FOREMAN DML
Division of Termcon
WL Water checked 1 day A.B. APPROVED NRS JOB a 20945233
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Boring and depth (ft) Classification DD MC%
1 3 3.0 1 Sandy Lean Clay W/ Siltstone/Claystone 83 91
PROJECT
DATE'
CONSOLIDATION TEST
Empire Laboratories, Inc.
Fort Collins, Colorado
SUNM1VL&RY OF TEST RESULTS
PROJECT NO. 20945233
Boring
No.
Depth
Ft.
Moisture : Dry
Density
PCF)
Compressive
Strength
PSF)
Swell
Pressure
PSF)
Soluble
Sulfates
pH Liquid
Limit
X
Plasticity
Index
Group
Index
Classification
AASHTO
USCS
Resistivity
OHM -CM)
Penetration
Blow/In.'
1 5-1.5 2 35 13 5 A-6(5); CL 17/12
3-4 i1
4-5 9 1040* 0024 34/12
868A 11 50/9
14-14.4 10 50/5
2 5-1.5 12 32/12
3-4 8
4-4.7 8 420* 50/8
8-8.6 11 50/7
14-14.3 11 50/4
3 5-1.5 7 27/12
34 11 85 135
4-5 15 31/12
8-8.9 14 850* 50111
14-14.8 13 50110
denotes remolded sample
DRILLING AND EXPLORATION
DRILLING & SAMPLING SYMBOLS:
SS : Split Spoon - 1%" I.D., 2" O.D., unless otherwise noted PS ; Piston Sample
ST : Thin -Walled Tube - 2" O.D., unless otherwise noted WS : Wash Sample
R Ring Barrel Sampler - 2.42" l.D., 3" O.D. unless otherwise noted.
PA : Power Auger FT : Fish Tail Bit
HA : Hand Auger AB : Rock Bit
DB : Diamond Bit = 4", N, B BS : Bulk Sample
AS : Auger Sample PM ; Pressure Meter
HS : Hollow Stem Auger DC : Dutch Cone
WB : Wash Bore
Penetration Test: Blows per foot of a 140 pound hammer falling 30 inches on a 2-inch O.D. split spoon, except where noted.
WATER LEVEL MEASUREMENT SYMBOLS:
WL : Water Level WS : While Sampling
WCI : Wet Cave in WD : While Drilling
DCI : Dry Cave in BCR : Before Casing Removal
AB : After Boring ACR : After Casting Removal
Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. in pervious soils, the
indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater
levels is not possible with only short term observations.
DESCRIPTIVE SOIL CLASSIFICATION
Soil Classification is based on the Unified Soil Classification
system and the ASTM Designations D-2487 and D-2488..
Coarse Grained Soils have more than 50% of their dry
weight retained on a #200 sieve; they are described as:
boulders, cobbles; gravel or sand: Fine Grained Soils have
less than 50% of their dry weight retained on a #200 sieve;
they are described as clays, if they are plastic, and silts if
they are slightly plastic or non -plastic. Major constituents
may be added as modifiers and minor constituents may be
added according to the relative proportions based on grain
size. In addition to gradation, coarse grained soils are
defined on the basis of their relative in -place density and
fine grained soils on the basis of their consistency.
Example: Lean clay with sand, trace gravel, stiff (CU; silty
sand, trace gravel, medium dense (SM).
CONSISTENCY OF FINE-GRAINED SOILS
Unconfined Compressive
Strength, au, psf Consistency
500 Very Soft
500 - 11000 Soft
1,001 - 2,000 Medium
2,001 - 4,000 Stiff
4,001 - 8,000 Very Stiff
8,001 - 16,000 Very Hard
RELATIVE DENSITY OF COARSE -GRAINED SOILS:
N-Blows/ft Relative Density
0-3 Very Loose
4-9 Loose
10-29 Medium Dense
30-49 Dense
50=80 Very .Dense
80 + Extremely Dense
PHYSICAL PROPERTIES OF BEDROCK
DEGREE OF WEATHERING:
Slight Slight decomposition of parent material on
joints. May be color change.
Moderate Some decomposition and color change
throughout.
High Rock highly decomposed, may be extremely
broken.
HARDNESS AND DEGREE OF CEMENTATION:
Limestone and Dolomite:
Hard Difficult to scratch with knife.
Moderately Can be scratched easily with knife,
Hard Cannot be scratched with fingernail.
Soft Can be scratched with fingernail.
Shale. Siitstone and Claystone:
Hard Can be scratched easily with knife, cannot
be scratched with fingernail.
Moderately Can be scratched with fingernail.
Hard
Soft Can be easily dented but not molded with
fingers.
Sandstone and Conglomerate:
Well Capable of scratching a knife blade.
Cemented
Cemented Can be scratched with knife.
Poorly Can be broken apart easily with fingers.
Cemented
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
UNIFIED SOIL CLASSIFICATION SYSTEM
Soil Classification
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests° Group
Sym691 Group Name'
Coarse -Grained Gravels more than Clean Gravels Less
Cu > 4 and 1 < Cc <36 GW Well -graded gravelSoilsmorethan50% of coarse than 5% fines
50% retained on fraction retained on
No. 260 sieve No. 4 sieve Cu < 4 and/or t > Cc > 31 _ . GP Poorly graded grayi
Gravels with Fines
c Fines classify as ML or MHmorethan12% fines GM Silty gravel,G,H
Sands 50% or more Clean Sands Less Cu > 6 and 1 < Cc < 36 SW Well -graded sand'
of coarse fraction than 5% fines'
passes No. 4 sieve Cu < 6 and/or 1 > Cc > 36 SP Poorly graded sand'
Sands with Fines Fines classify as M_ L or M_ H SM Silty sand°•i'u
more than 12% fines°
Fines Classify as CL or CH SC Clayey sandy Fu
Fine -Grained Soils Silts and Clays inorganic PI > 7 and plots on or above "A line) CL Lean clay'`-"
50% or more
passes the
Liquid limit less
than 50 PI < 4 or plots below "A" line) ML_ SiltK`•"'
No. 200 sieve
organic Liquid limit - oven dried Organic clay""
0.75 OL
Liquid limit - not dried Organic silt"A•"•o
Silts and Clays inorganic PI pints on or above "A" line CH Fat clayluO
Liquid limit 50
or more PI lots below "A" line MH Elastic SiltK4M
organic . Liquid limit - oven dried _ Organic clay"i"
0.75 OH
Liquid limit - not dried Organic siltCL.M.o
Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat
ABased on the material passing the 3-in. If soil contains 15 to 29% plus No. 200, add
75-mm) sieve aCu=D (.Dso)' Cc = With, sand" or "with gravel", whichever is
if field sample contained cobbles or
sodD}o Din x D60 predominant.
boulders, or both, add "with cobbles or 4f soil contains > 30% plus No. 200
boulders, or both" to group name. predominantly sand, add "sandy" to group
Gravels with 5 to 12% fines require dual if soil contains> 15% sand, add "with name
symbols: sand" to group name. Mif soil contains > 30% plus No. 200,
GW-GM well -graded gravel with silt 9f fines classify as CL-ML, use dual symbol predominantly gravel, add "gravelly" to group
GW-GC well -graded gravel with clay GC -GM, or SC-SM. name.
GP -GM poorly graded gravel with silt If fines are organic, add 'with organic fines" PI > 4 and plots on or above "A" line.
GP -GC poorly graded gravel with clay to group name. PI < 4 or plots below "A" line.
Sands with 5 to 12% fines require dual hf soil contains > 15% gravel, add "with PPI plots on or. above "A" line.
symbols: gravel" to group name. oPl plots. below "A" line,
SW-SM well -graded sand with silt tf Atterberg limits plot in shaded area, soil is
SW -SC well -graded sand with clay a CL-ML, silty clay.
SMM poorly graded sand with sift
SP-SC poorly graded sand with clay
v
is7
40
U
Ca 20
a
10
7
4.
0
and R e,°Yed rro06106 of oemo"-
Iq(i0° of •A -. r".
MMzo d at PI - 4 to LL 25.5 J; "I i
Nm P10.73(LL=20) O P LL
Verticalq 6G
ZL
ON, MH
OR OH ML
oR OL 0
10 16 20 30 40 50 60 70 80 60 100 11c LIQUID
LIMIT (LL) Empire
Laboratories, Inc. A
Division of The Terracon Companies, Inc.
ROCK CLASSIFICATION
Based on ASTM C-294)
Sedimentary Rocks
Sedimentary rocks are stratified materials laid down by water or wind. The sediments may be
composed of particles of pre-existing rocks derived by mechanical weathering, evaporation or by
chemical or organic origin. The sediments are usually indurated by cementation or compaction.
Chart Very fine-grained siliceous rock composed of micro -crystalline or crypto-
crystalline quartz, chalcedony or opal. Chert is various colored, porous to
dense, hard and has a conchoidal to splintery fracture.
Claystone Fine-grained rock composed of or derived by erosion of silts and clays or any
rock containing clay. Soft massive; gray, black, brown, reddish or green and
may contain carbonate minerals.
Conglomerate Rock consisting of a considerable amount of rounded gravel, sand and cobbles
with or without interstitial or cementing material. The cementing or interstitial
material may be quartz, opal, calcite, dolomite, clay, iron oxides or other
materials.
Dolomite A fine-grained carbonate rock consisting of the mineral dolomite [CaMg
CO3)21. May contain noncarbonate impurities such as quartz, chert, clay
minerals,.organic matter, gypsum and sulfides. Reacts with hydrochloric acid
HCL).
Limestone A fine-grained carbonate rock consisting of the mineral calcite (CaCo). May
contain noncarbonate impurities such as quartz, chert, clay minerals, organic
matter, gypsum and sulfides. Reacts with hydrochloric acid (HCL).
Sandstone Rock consisting of particles of sand with or without interstitial and cementing
materials. The cementing or interstitial material may be quartz, opal, calcite,
dolomite, clay, iron oxides or other material.
Shale Fine-grained rock composed of, or derived by erosion of silts and clays or any
rock containing clay. Shale is hard, platy, or fissile may be gray, black,
reddish or green and may contain some carbonate minerals (calcareous shale).
Siltstone Fine grained rock composed of, or derived by erosion of silts or rock
containing silt. Siitstones consist predominantly of silt sized particles (0.0625
to 0.002 mm in diameter) and are intermediate rocks between claystones and
sandstones, may be gray, black, brown, reddish or green and may contain
carbonate minerals.
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
LABORATORY TESTS
SIGNIFICANCE AND PURPOSE
TEST SIGNIFICANCE PURPOSE
California Used to evaluate the potential strength of subgrade soil, subbase, Pavement
Bearing and base course material, including recycled materials for use in Thickness
Ratio road and airfield pavements. Design
Consordation Used to develop an estimate of both the rate and amount of both Foundation
differential and total settlement of a structure. Design
Direct Used to determine the consolidated drained shear strength of soil Bearing Capacity,
Shear or rock. Foundation Design &
Slope Stability
Dry Used to determine the in -place density of natural, inorganic, fine- Index Property
Density grained. soils. _ _ Soil Behavior
Expansion Used to measure the expansive potential of fine-grained soil and to Foundation & Slab
provide a basis for swell potential classification. Design
Gradation Used for the quantitative determination of the distribution of Soil
particle sizes in soil. Classification
Liquid & Used as an integral part of engineering classification systems to Soil
Plastic Limit, characterize the fine-grained fraction of soils, and to specify the Classification
Plasticity_ Index fine-grained fraction of construction materials.
Oxidation- Used to determine the tendency of the soil to donate or accept Corrosion
Reduction electrons through a change of the oxidation state within the soil. Potential
Potential
Used to determine the capacity of soil or rock to conduct a liquid Groundwater
Permeability
or gas. Flow Analysis
Used to determine the degree of acidity or alkalinity of a soil. Corrosion
pH Potential
Used to indicate the relative ability of a soil medium to carry Corrosion
Resistivity electrical currents. Potential
Used to evaluate the potential strength of subgrade soil, subbase, Pavement
R-Value and base course material, including recycled materials for use in Thickness
road and airfield pavements. Design
Soluble Used to determine the quantitative amount of soluble sulfates Corrosion
Sulphate within a soil mass. Potential
Used to determine the quantitative amounts of sulfides within a Corrosion
Sulfide Content soil mass. Potential
To obtain the approximate compressive strength of soils that Bearing Capacity
Unconfined possess sufficient cohesion to permit testing in the unconfined Analysis for
Compression
state. _ Foundations
water Used to determine the quantitative amount of water in a soil mass. Index Property
Content Soil Behavior
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
REPORT TERMINOLOGY
Based on ASTM D653)
Allowable Soil The recommended maximum contact stress developed at the interface of the
Bearing Capacity foundation element and the supporting material.
Alluvium Soil, the constituents of which have been transported in suspension by flowing
water and subsequently deposited by sedimentation.
Aggregate Base A layer of specified material placed on a subgrade or subbase usually beneath
Course slabs or pavements.
Backfill A specified material placed and compacted in a confined area.
Bedrock A natural aggregate of mineral grains connected by strong and permanent
cohesive forces. Usually requires drilling, wedging, blasting or other methods of
extraordinary force for excavation.
Bench A horizontal surface in a sloped deposit.
Caisson (Drilled pier A concrete foundation element cast in a circular excavation which may have an
or Shaft) enlarged base. Sometimes referred to as a cast -in -place pier or drilled shaft.
Coefficient of A constant proportionality factor relating normal stress and the corresponding
Friction shear stress at which sliding starts between the two surfaces.
Coluuvium Soil, the constituents of which have been deposited chiefly by gravity such as
at the foot of a slope or cliff.
Compaction The densification of a soil by means of mechanical manipulation.
Concrete Slab -on- A concrete surface layer cast directly upon a base, subbase or subgrade, and
Grade typically used as a floor. system.
Differential Unequal settlement or heave between, or within foundation. elements of a
Movement structure.
Earth Pressure The pressure or force exerted by soil on any boundary such as a foundation
Wall.
ESAL Equivalent Single Axle Load, a criteria used to convert traffic to a uniform
standard, 0 8,000 pound axle loads).
Engineered Fill Specified material placed and compacted to specified density and/or moisture
conditions under observations of a representative of a geotechnical engineer.
Equivalent Fluid A hypothetical fluid having a unit weight such that it will produce a pressure
against a lateral support presumed to be equivalent to that produced by the
actual soil. This simplified approach is valid only when deformation conditions
are such that the pressure increases linearly with depth and the wall friction is
neglected.
Existing Fill (or Materials deposited through the action of man prior to exploration of the site.
man-made fill)
Existing Grade The ground surface at the time of field exploration.
Empire Laboratories, Inc.
A Division of The Terracon Companies, Inc.
REPORT TERMINOLOGY
Based on ASTM D653)
Expansive Potential The potential of a soil to expand (increase in volume) due to absorption of
moisture.
Finished Grade The final grade created as a part of the project.
Footing A portion of the foundation of a structure that transmits loads directly to the
soil.
Foundation The lower part of a structure that transmits the loads to the soil or bedrock.
Frost Depth The depth of which the ground becomes frozen during the winter season.
Grade Beam A foundation element or wall, typically constructed of reinforced concrete,
used to span between other foundation elements such as drilled piers.
Groundwater Subsurface water found in the zone of saturation of soils, or within fractures
in bedrock.
Heave Upward movement.
Lithologic The characteristics which describe the composition and texture of soil and
rock by observation.
Native Grade The, naturally occuring ground surface.
Native Soil Naturally occurring on -site soil, sometimes referred to as natural soil.
Optimum Moisture The water content at which a soil can be compacted to a maximum dry unit
Content weight by a given compactive effort.
Perched Water Groundwater, usually of limited area maintained above a normal water
elevation by the presence of an intervening relatively impervious continuing
stratum.
Scarify To mechanically loosen soil or break down existing soil structure.
Settlement Downward movement.
Skin Friction (Side The frictional resistance developed between soil and an element of structure
Shear) such as a drilled pier or shaft..
Soil (earth) Sediments or other unconsolidated accumulations of solid particles produced
by the physical and chemical disintegration of rocks, and which may or may
not contain organic matter.
Strain The change in length per unit of length in a given direction.
Stress The force per unit area acting within a soil mass.
Strip To remove from present location.
subbase A layer of specified material in a pavement system between the subgrade and
base course,
Subgrade The soil prepared and compacted to support a structure, slab or pavement
system.
Empire Laboratories, hic.
A Division of The Terracon . Companies, Inc.